OpenDNSUpdater V2.1.0

Change log:

fed615c - Started to work on #13. App version bumped to 2.1.0
b445b58 - AppIntro incorporated. Explanations are given to the user
956acf4 - If app has been updated, use old configuration
c89d130 - Use AppIntro policies
935bbcc - Moved permissions to application intro.
07d7767 - Added basic showcase functions to show and explain how to use the app
03c4fe9 - Added Spotlight to explain the main view. Updated licences list.
e4b606e - Fixed minors bugs.
cdce5ba - Fixed typos